We use this contraption to add distilled water to new or used (punctured) IV bags...

On the top we have a permanent bag, with a slit cut out (reinforced the bottom of the cut with duct tape).This is where you pour the distilled water you want in your reusable bag.

On the bottom is a "holder" for the IV bag you want refilled. We used an empty 'cleaner wipes' canister.

When filling a bag that hasn't been punctured we use a blunt tip...(side tip - you can drain bags this way - just put a blunt tip in, turn it upside down, and leave it in a drain for an hour)

If you are filling a bag that has already been punctured, you can use a home made IV top...

Just a close up of the two options...

I duct taped their caps to the side of the pole so they don't get lost, and ease of access...

We have a drugs/fluids/blood area in our lab where the students go to get IV bags. Depending on the users and/or fidelity we will either leave out 'new' non-punctured bags or 'used' punctured bags with a closed IV line already inserted.

I haven't messed with this build in a bit, but I'm sure some of you could offer some design improvements... let me know...